Following patent documents published by the Japan Patent Office propose methods of transmitting power to a battery of an electric automobile wirelessly using electromagnetic induction, microwaves, electric field resonance, or magnetic field resonance instead of a transmission cable.                JP2009-106136A, published on May 14, 2009;        JP2002-152996A, published on May 25, 2002;        JP2008-054424A, published on Mar. 5, 2008;        JP2006-174676A, published on Jun. 29, 2006; and        Japan Patent Serial No. 3985390, published on Oct. 3, 2007.        
“Wireless Power Transfer via Strongly Coupled Magnetic Resonances”, Science vol. 317, pages 83-86, published on Jun. 6, 2007 teaches power transmission techniques using electric field resonance or magnetic field resonance, with which several kilowatts of power can be transferred over a comparatively large gap of several meters, for example.